This standard provided the calibration means of digital seismometer .
标准简介：本标准规定了数字地震仪.
Seismometer is a great invention that was invented in east han dynasty by zhang heng .
地动仪是我国东汉时期张衡的一项大发明。
Each has a seismometer for detecting earthquakes , an infrared sensor to detect heat from volcanic explosions , a sensor to detect ash clouds , and a global positioning system to sense the ground bulging and pinpoint the exact location of seismic activity .
